The Model DR-299 Nucliometer was a "high end" GM survey meter produced by the Detectron
Corporation of North Hollywood, California.

To obtain maximum sensitivity, the Nucliometer had 24 thin-walled GM tubes
(you read that right, 24 of them) inside
the case. There was one more GM tube in the external probe.

Despite Detectron's claim that the instrument was rugged, almost all
the tubes are collapsed in every Model 299 you encounter today. The
customer service folks at Detectron must have had their hands full when
the company started to market this thing.

Quoting the company's
description of the DR-299: "one of the most versatile of all uranium
prospecting instruments, the Nucliometer is responsible for many of the best
uranium discoveries. It has detected many deposits previously missed by
other, less sensitive instruments. The DR-299 can be used for ordinary
prospecting, to check individual specimens, to make field assay estimations,
in grid map survey work and in airborne survey work. In short, there is no
application in which the DR-299 is not suitable. Not only is the Nucliometer
versatile, but it is also extremely reliable. The instrument, unlike all
scintillation counters, is not affected by heat and vibration, yet has
extreme sensitivity to radiation."

So highly did the company think of
this instrument that they referred to it as the "greatest advancement in
uranium detection in years."

The photograph below shows the inside of the unit. The ends of the 24 GM
tubes can be seen in the bottom of the case. Trust me, they are all
collapsed. The two sets of "B" batteries can also be seen, but the three 1.5
volt D cells are missing.

The Model 299A (not in the ORAU collection) was designed for airborne
surveys. It came with an external meter that could be connected to
the instrument via a ten-foot cable. This allowed the pilot to make readings
in the cockpit while the
instrument was located in the plane's luggage compartment. If the detector
was in the cockpit, there could be a high background if the plane had any
any radioluminescent dials.

The Model 390-B Nucliometer (not in the ORAU collection) was also intended
for airborne surveys. The main difference was that the 390-B came with 24
Victoreen 6306 bismuth-lined GM tubes. The 24 tubes in the Model 299 and
299A Nucliometers were a mix 6306 and less sensitive 1B85 tubes.

Since Detectron was located
in North Hollywood, it was only natural that their instruments were used in a
number of motion pictures, e.g., TheBrain from Planet Arous. In
fact, Larry Cassingham, the company president, served as the Technical
Director for a number of films, e.g., Zombies from the Stratosphere with
Leonard Nimoy and The Atomic Kid starring Mickey Rooney.